Cayalyst system

ABSTRACT

A catalyst system includes a transition metal salt containing a halo group, an acetate group, or a combination thereof, and an organic phosphine ligand. The molar ratio of the organic phosphine ligand to the transition metal salt is greater than 0 and less than or equal to 50.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a divisional application of U.S. patent applicationSer. No. 14/140,479, filed on Dec. 25, 2013, now allowed. The priorapplication Ser. No. 14/140,479 claims the priority benefit of Taiwanapplication serial no. 102138524, filed on Oct. 24, 2013. The entiretyof each of the above-mentioned patent applications is herebyincorporated by reference herein and made a part of this specification.

TECHNICAL FIELD

The disclosure relates to a catalyst system.

BACKGROUND

In the resin industry, a resin having a cyclic carbonate functionalgroup may be used in the synthesis of non-isocyanate polyurethane resin(NIPU), and the isocyanate compounds having higher toxicity areabrogated from being applied in the synthesizing process. In theindustry, the isocyanate monomer is produced using phosgene, in whichboth the raw materials and the end products are highly toxic chemicals.Accordingly, greener materials, for replacing the isocyanatepolyurethane resin material, gradually become the focus of attention.Since the non-isocyanate material do not have moisture sensitiveisocyanate functional groups, the storage and processing conditions arepreferred over those of a conventional polyurethane resin.

The critical material for the non-isocyanate polyurethane resin is acyclic carbonate compound, which is prepared by using carbon dioxide andan epoxy compound. The method of synthesis includes utilizing a Lewisbase, an ionic liquid, a metal complex, a heterogeneous metal salt, asilica supported catalyst, an oxidized metal salt porous material or anion exchange resin as a catalytic system to catalyze the reaction ofcarbon dioxide and the epoxy compound. Among the above catalysts, thesalt type or the ionic liquid catalyst is the most commonly used.However, these catalysts are usually less soluble in an epoxy compound.Consequently, the amount of catalyst used is increased and the reactionconditions are adjusted to high temperature and high pressure in orderto achieve the desired conversion rate. Further, by-products aregenerated. Alternatively, ligands synthesized through special designs orexpensive metal ions may be utilized to prepare the catalyst. However,not only commercial production becomes difficult, the product costincreases and the recycling of catalyst is inevitable. Due to abovereasons, the bar of the fabrication technology of cyclic carbonate israised, and the yield of non-isocyanate polyurethane resin cannot beeffectively improved.

Accordingly, the development of a new generation of catalyst systemhaving high reaction activity, being producible under moderate reactionconditions, being able to preclude the requisite of being recycled fromthe product and being cost-effective has become the focus of attentionin the fabrication technology of cyclic carbonate.

SUMMARY

An exemplary embodiment of the disclosure provides a catalyst systemthat includes a transition metal salt and an organic phosphine ligand,wherein the transition metal salt includes a halo group, an acetategroup, or a combination thereof. The molar ratio of the organicphosphine ligand to the transition metal salt is greater than 0 and lessthan or equal to 50.

In the following detailed description, for purposes of explanation,numerous specific details are set forth in order to provide a thoroughunderstanding of the disclosed embodiments. It will be apparent,however, that one or more embodiments may be practiced without thesespecific details.

DETAILED DESCRIPTION OF DISCLOSED EXEMPLARY EMBODIMENTS

In one exemplary embodiment of the disclosure, the catalyst systemincludes a transition metal salt and an organic phosphine ligand. Thetransition metal salt includes at least a halo group, an acetate groupor a combination thereof. The molar ratio of the above-mentioned organicphosphine ligand to the above-mentioned transition metal salt may begreater than 0 but less than or equal to 50, for example, greater than 0but less than or equal to 8. If the ratio of the organic phosphineligand is too high, the organic phosphine ligand may not be effectivelydispersed in the system, and the subsequent application of the cycliccarbonate is adversely affected. Further, the above-mentioned catalyticsystem may also contain a halogen-containing compound, and the molarratio of the above-mentioned halogen-containing compound to thetransition metal salt may be greater than 0 but less than or equal to50, for example, greater than 0 but less than or equal to 10. If theratio of the above-mentioned halogen-containing compound is too high,the halogen-containing compound may not be effectively dispersed in thesystem, and the subsequent application of the cyclic carbonate isaffected.

In an exemplary embodiment, the above-mentioned transition metal saltincludes halogen-containing transition metal salt, such as CoBr₂, RhCl₃,RuCl₂, or FeCl₂. Other effective halogen-containing transition metalsalt may include PdX_(n) (palladium halides, since valance varies,halides are represented by the general formula X_(n)), FeCl₃, AlCl₃,TiCl₄, ScX₂, ScX₃ (scandium halides), VX_(n) (vanadium halides), Z_(n)X₂(zinc halides), CuX₂ (copper halides), tin halides (SnX₂), ZrX_(n)(zirconium halides), MoX_(n) (molybdenum halides), WX_(n) (tungstenhalides), PtX_(n) (pallatinum halides), BiX_(n) (bismuth halides), etc,wherein X represents chlorine, bromine, or iodine; n is greater than 1and less than or equal to 6, commonly 2 or 4 according to valencenumber.

In another exemplary embodiment, the above-mentioned transition metalsalt includes a transition metal salt containing an acetate group, suchas Co(OAc)₂, Zn(OAc)₂, Pd(OAc)₂, Fe(OAc)₂, Fe(OAc)₃, Cu(OAc)₂, Cs(OAc),Rh(OAc)₂(dimer), Pb(OAc)₂, Sb(OAc)₃, La(OAc)₃, Bi(OAc)₃, Cd(OAc)₂,Y(OAc)₃, or Sc(OAc)₃.

In one exemplary embodiment, the above-mentioned halogen-containingcompound includes, but not limited to, tetrabutylammonium chloride,(TBAC), anilinium chloride, benzalkonium chloride, benzoxonium chloride,cetrimonium chloride, cetylpyridinium chloride, choline chloride,didecyl dimethyl ammonium chloride, dimethyl dioctadecyl ammoniumchloride, stearalkonium chloride, tetramethyl ammonium chloride,tetrabutylammonium bromide (TBAB), tetrabutylammonium iodide (TBAI),tetraethylammonium bromide, domiphen bromide, benzododecinium bromide,(1-ethoxy-1-oxohexadecan-2-yl)-trimethylazanium bromide, cetrimoniumbromide, emepronium bromide, tetrabutylammonium tribromide,tetraoctylammonium bromide, thonzonium bromide, dithiazanine iodide,methiodide, or tetraethylammonium iodide.

In one exemplary embodiment, the above-mentioned organic phosphineligand includes, but not limited to, triphenyl phosphine (PPh₃),triphenyl phosphine oxide (OPPh₃), Poly(dipropylene glycol) phenylphosphite, tricyclohexyl phosphine (PCy₃), Tris(2,4-di-tert-butylphenyl) phosphite, triphenyl phosphite, ordiphenylmethyl phosphine.

In one exemplary embodiment, the molar ratio of above-mentioned organicphosphine ligand to the transition metal salt is not particularlylimited, as long as it is greater than 0, for example, greater than 0but less than or equal to 50. In another example, the molar ratio may begreater than 0 but less than or equal to 8. The molar ratio of theabove-mentioned halogen-containing compound to the cobalt in thetransition metal salt is not particular limited, as long as it isgreater than 0, for example, greater than 0 but less than or equal to50. In another example, the molar ratio may be greater than 0 but lessthan or equal to 10.

The fabrication method according to an exemplary embodiment includesrendering an epoxy compound and carbon dioxide to be in contact with theabove-mentioned catalyst system in a reactor to form a cyclic carbonatecompound. The epoxy compound of the embodiment may include any typicalepoxy compound used in the preparation of a cyclic carbonate compoundand is not particularly limited. The epoxy compound of the embodimentmay include, but not limited to, 1,4-butanediol diglycidyl ether (BDGE),1,4-cyclohexanedimethanol diglycidyl ether (a mixture of trans and cis,CHDDG), trimethylolpropane triglycidyl ether (TMPTGE), etc. Further,based on the amount of the epoxy compound used as a calculationstandard, the amount of the catalyst system used may be between 1 mmol %to 50 mmol %, for example, between 1 mmol % to 10 mmol %. It is notbeneficial to the reaction if too much catalyst is being used. In thisexemplary embodiment, the reaction temperature is lower than 100° C.,for example, greater than room temperature but lower than 100° C., forexample, between 50° C. to 90° C. If the temperature is too low, thereaction time is extended in order to achieve the preferred cycliccarbonate conversion rate. The pressure of carbon dioxide is between 1to 20 atm, for example, between 1 to 10 atm. If the pressure is toohigh, the required equipment specifications have to be strict and theproduction of cyclic carbonate will not be economical. The reaction timemay be between 1 to 20 hours, for example, between 1 to 8 hours. It isnot beneficial to the conversion rate if the reaction time is too long.

In the above exemplary embodiment, a cyclo-addition reaction occurs whenthe catalyst system comprising transition metal salt and organicphosphine ligand in the presences of carbon dioxide and an epoxycompound. The catalyst system may further include halogen-containingcompound. The catalyst system does not result in the generation ofpolycarbonate but instead induces the generation of cyclic carbonate.Further, the above-mentioned catalyst system has a more superior andstable chemical activity; using a small amount thereof is sufficient toprovide a desired cyclic carbonate conversion rate. The catalyst systemof the disclosure provides a cyclic carbonate product with a highconversion rate under moderate reaction conditions.

Several experiments were conducted to demonstrate the effects of theexemplary embodiments of the disclosure. It should be understood thatthese experiments are presented by way of examples and not by way oflimitation.

EXAMPLE 1

An epoxy compound 1,4-butanediol diglycidyl ether (BDGE, cas no.2425-79-8, 15 g) and cobalt bromide (CoBr₂ anhydrous, 81 mg), andtriphenyl phosphine (PPh3, 195 mg) were placed in a reactor. The reactorwas then sealed and the air inside was drawn out by vacuum. Carbondioxide was supplied to the reactor. After repeating the above processfor three times, carbon dioxide was delivered into the reactor and thepressure of the reactor could reach 8 atm. The mixture was heated to 90°C. and was spun at a rate of 500 rpm. The mixture was allowed to bestirred for 4 hours. The reaction equation of Example 1 is as follow:

The gas was released from the reactor until atmospheric pressure wasreached. The heating was halted for the reactor temperature dropping toroom temperature. The product was then removed and the conversion rateof the cyclic carbonate of the product was analyzed by ¹H NMR spectrum.The conversion rate of the cyclic carbonate was determined to be 85% andwas recorded in Table 1.

EXAMPLE 2

An epoxy compound 1,4-butanediol diglycidyl ether (BDGE, 250 g), Cobaltacetate tetrahydrate (Co(OAc)₂.4H₂O, 1.54 g), triphenyl phosphine (PPh3,3.25 g) and (tetrabutylammonium bromide (TBAB, 3.99 g) were placed in areactor. The reactor was sealed and the air therein was drawn out byvacuum. Carbon dioxide was provided to the reactor. After repeating theabove process step for three times, carbon dioxide was delivered intothe reactor and the pressure inside the reactor could reach 8 atm. Themixture was then heated to 90° C. and was spun at a rate of 500 rpm. Themixture was allowed to be stirred for 4 hours. The gas was then releasedfrom the reactor until atmospheric pressure was reached. Further, theheating was halted for the reactor temperature dropping to roomtemperature. The product was then removed. The conversion rate of thecyclic carbonate of the product analyzed by ¹ H NMR spectrum wasdetermined to be greater than 99% and was recorded in Table 1.

EXAMPLE 3

An epoxy compound 1,4-cyclohexanedimethanol diglycidyl ether (CHDDG, amixture of cis and trans, 15 g), cobalt acetate tetrahydrate,(Co(OAc)₂.4H₂O, 72 mg), triphenyl phosphine (PPh₃, 153 mg) andtetrabutylammonium bromide (TBAB, 189 mg) were placed in a reactor. Thereactor was sealed and the air inside was drawn out by vacuum. Carbondioxide was supplied to the reactor. After repeating the above processfor three times, carbon dioxide was delivered into the reactor and thepressure inside the reactor could reach 8 atm. The mixture was thenheated to 90° C. and was spun at a rate of 500 rpm. The mixture wasstirred for 4 hours. The gas was then released from the reactor untilatmospheric pressure was reached. Further, the heating was halted forthe reactor temperature dropping to room temperature. The product wassubsequently removed. The conversion rate of the cyclic carbonate of theproduct was analyzed by ¹ H NMR spectrum and was determined to be 78%.The result is recorded in Table 1.

EXAMPLE 4

An epoxy compound trimethylolpropane triglycidyl ether (TMPTGE 15 g),cobalt acetate tetrahydrate (Co(OAc)₂.4H₂O, 62 mg) as catalyst,triphenyl phosphine (PPh₃, 130 mg) and tetrabutylammonium bromide (TBAB,160 mg) were placed in a reactor. The reactor was sealed and the airinside was drawn out by vacuum. Carbon dioxide was supplied to thereactor. After repeating the above process for three times, carbondioxide was delivered into the reactor and the pressure inside thereactor could reach 8 atm. The mixture was then heated to 90° C. and wasspun at a rate of 500 rpm. The reaction was conducted for 4 hours.Thereafter, the gas was released from the reactor until atmosphericpressure was reached. Further, the heating was halted for the reactortemperature dropping to room temperature and the product was removed.The conversion rate of the cyclic carbonate of the product was analyzedby ¹ H NMR spectrum and was determined to be 81%. The result is recordedin Table 1.

COMPARATIVE EXAMPLE 1

An epoxy compound 1,4-butanediol diglycidyl ether (15 g) andtetrabutylammonium bromide (239 mg) were placed in a reactor. Thereactor was sealed and the reaction was carried out for 4 hoursfollowing the process similar to Example 1. The product was then removedat room temperature. The conversion rate of the cyclic carbonate of theproduct was analyzed by ¹ H NMR spectrum and was determined to be 67%.The result is recorded in Table 1.

COMPARATIVE EXAMPLE 2

An epoxy compound 1,4-butanediol diglycidyl ether (15 g), triphenylphosphine (PPh₃, 195 mg) and tetrabutylammonium bromide (239 mg) wereplaced in a reactor. The reactor was sealed and the reaction was carriedout for 4 hours following the process similar to Example 1. The productwas then removed at room temperature. The conversion rate of the cycliccarbonate of the product was analyzed by ¹ H NMR spectrum and wasdetermined to be 68%. The result is recorded in Table 1.

COMPARATIVE EXAMPLE 3

An epoxy compound 1,4-butanediol diglycidyl ether (BDGE, 15 g) andcobalt acetate tetrahydrate (Co(OAc)₂.4H₂O, 92 mg) were placed in areactor. The reactor was sealed and a reaction was carried out for 4hours following the process similar to Example 1. The product was thenremoved at room temperature. The conversion rate of the cyclic carbonateof the product was analyzed by ¹H NMR spectrum and was determined to be0%. The result is recorded in Table 1.

TABLE 1 (the addition amount of Co(OAc)₂•4H₂O was 10 mmol % of the epoxycompound) Organic Halogen- Phosphine Containing Ligand Compound ReactionConversion Transition Molar Molar Temp Rate Metal Salt Type Ratio TypeRatio (° C.) (%) Example 1 CoBr₂ PPh₃ 2 — — 90 85 Example 2 Co(OAc)₂PPh₃ 2 TBAB 2 90 >99 Example 3 Co(OAc)₂ PPh₃ 2 TBAB 2 90 78 Example 4Co(OAc)₂ PPh₃ 2 TBAB 2 90 81 Comparative — — — TBAB 2 90 67 Example 1Comparative — PPh₃ 2 TBAB 2 90 68 Example 2 Comparative Co(OAc)₂ — — — —90 0 Example 3

According to the results summarized in Table 1, the catalyst system ofthe exemplary embodiments of the disclosure provided a better conversionrate of cyclic carbonate. Further, the application of a substantialamount of catalyst or solvent was also precluded.

PRACTICAL EXAMPLE

The product of example 1 (BDCE, 1,4-butandiol dicarbonate ether, 2.61 g)and epoxy resin monomer 1010 (bisphenol A diglycidyl ether, 3.06 g) weremixed evenly as agent A. Further, m-xylenediamine (2.45 g) and tripentylamine (10 mg) were evenly mixed as agent B. The above agent A and agentB were mixed evenly in an aluminum plate and the resulting mixture wasplaced at room temperature for 48 hours for the mixture to solidify. Thereactants of the practical example are as shown below:

The product obtained was measured using Shore A durometer and thehardness was determined to be 83. Accordingly, it was confirmed that thecatalyst system of the disclosure could be used to synthesize apolycarbonate resin product.

The effects of the ratio of each component in the catalyst system on theconversion rates are described in the following Examples 5 to 9.

EXAMPLES 5 TO 9

An epoxy compound (1,4-butanediol diglycidyl ether, BDGE, 15 g), cobaltacetate tetrahydrate (Co(OAc)₂.4H₂O, 92 mg, 10 mmol%), triphenylphosphine (PPh₃) and tetrabutylammonium bromide (TBAB) were placed in areactor, followed by sealing the reactor. The ratio of triphenylphosphine (PPh₃) to cobalt and the ratio of tetrabutylammonium bromide(TBAB) to cobalt were different in different Examples, as shown in Table2. Similar to the above Example 1, the reaction was carried out for 4hours and the product was removed from the reactor after the reactor hadreturn to room temperature and atmospheric pressure. The conversion rateof the cyclic carbonate of the product was analyzed by ¹H NMR spectrumand the result is recorded in Table 1.

TABLE 2 (the addition amount of Co(OAc)₂•4H₂O was 10 mmol % of the epoxycompound) Organic Halogen- Phosphine Containing Ligand Compound ReactionConversion Molar Molar Temp Rate Example Type Ratio Type Ratio (° C.)(%) 5 PPh₃ 2 TBAB 2 90 >99 6 PPh₃ 8 TBAB 2 90 91 7 PPh₃ 2 TBAB 2 90 96 8PPh₃ 1 TBAB 2 90 91 9 PPh₃ 2 TBAB 10 90 >99

According to Table 2, with the ratios of the organic phosphine ligand orthe halogen-containing compound of the catalyst system of thisdisclosure varying, desired conversion rates of cyclic carbonate werenevertheless achieved.

The effects of reaction temperature on the conversion rate of cyclecarbonate are described in Example 5 and Example 10 below.

EXAMPLE 10

Aside from the reaction temperature, the composition and the processperformed of Example 10 were similar to those of Example 5. The productwas removed from the reactor at atmospheric pressure and roomtemperature. The conversion rate of the cyclic carbonate of the productwas analyzed by ¹ H NMR spectrum and is recorded in Table 3.

TABLE 3 (the addition amount of Co(OAc)₂•4H₂O was 10 mmol % of the epoxycompound) Organic Halogen- Phosphine Containing Ligand Compound ReactionConversion Molar Molar Temp Rate Example Type Ratio Type Ratio (° C.)(%) 5 PPh₃ 2 TBAB 2 90 >99 10 PPh₃ 2 TBAB 2 75 79

Based on the results summarized in Table 3, even at low temperature, thecatalyst system of the disclosure provided good conversion rate ofcyclic carbonate.

The effects of using different organic phosphine ligands in the catalystsystem on the conversion rate of cycle carbonate are described inExample 5 and Examples 11 to 16 below.

EXAMPLES 5, 11 TO 16

An epoxy compound (1,4-butanediol diglycidyl ether, BDGE, 15 g), cobaltacetate tetrahydrate (Co(OAc)₂.4H₂O, 92 mg), tetrabutylammonium bromide(TBAB, 239 mg) and various types of organic phosphine ligand were placedin a reactor, followed by sealing the reactor. Similar to Example 1, thereaction was carried out for 4 hours and the product was removed fromthe reactor after the reactor had returned to room temperature andatmospheric pressure. The conversion rate of cyclic carbonate of theproduct was analyzed by ¹ H NMR spectrum and is recorded in Table 4.

TABLE 4 (the addition amount of Co(OAc)₂•4H₂O was 10 mmol % of the epoxycompound) Organic Halogen- Phosphine Containing Reaction ConversionLigand Compound Temp Rate Example Type Molar ratio Type Molar Ratio (°C.) (%) 5 PPh₃ 2 (194 mg) TBAB 2 90 >99 11 OPPh₃ 2 (206 mg) TBAB 2 90 8512 PPO 2 (287 mg) TBAB 2 90 86 13 PCy₃ 2 (208 mg) TBAB 2 90 85 14TTPTTBP 2 (480 mg) TBAB 2 90 80 15 P(OPh₃)₃ 2 (230 mg) TBAB 2 90 91 16MePPh₂ 2 (148 mg) TBAB 2 90 89

In Table 4, PPO in Example 12 represents (poly (dipropylene glycol)phenyl phosphite, average molecular weight is 386); PCy₃ in Example 13represents a toluene solution containing 30% of tricyclohexyl phosphine(PCy₃); TTPTTBP in Example 14 represents Tris(2,4-di-tert-butylphenyl)phosphite.

Based on the results summarized in Table 4, good conversion rates ofcyclic carbonate were achieved, even different organic phosphine ligandsof the catalyst system of the disclosure were used.

The effects of using different halogen-containing compounds in thecatalyst system on the conversion rate of cycle carbonate are describedin Example 5 and Examples 17 to 18 below.

EXAMPLES 17 TO 18

An epoxy compound (1,4-butanediol diglycidyl ether, BDGE, 15 g), cobaltacetate tetrahydrate (Co(OAc)₂.4H₂O, 92 mg), triphenyl phosphine (PPh₃,194 mg) and various halogen-containing compounds were placed in areactor, followed by sealing reactor. Similar to Example 1 above, thereaction was carried out for 4 hours and the product was removed fromthe reactor after the reactor had returned to room temperature andatmospheric pressure. The conversion rate of cyclic carbonate of theproduct was analyzed by ¹ H NMR spectrum and is recorded in Table 5.

TABLE 5 (the addition amount of Co(OAc)₂•4H₂O was 10 mmol % of the epoxycompound) Organic Halogen- Phosphine Containing Con- Ligand CompoundReaction version Molar Molar Temp Rate Example Type ratio Type Ratio (°C.) (%) 5 PPh₃ 2 TBAB 2 (239 mg) 90 >99 17 PPh₃ 2 TBAC 2 (206 mg) 90 8118 PPh₃ 2 TBAI 2 (274 mg) 90 >99

In Table 5, TBAB represents tetrabutylammonium bromide; TBAC representstetrabutylammonium chloride; TBAI represents tetrabutylammonium iodide.Based on the results summarized in Table 5, good conversion rates ofcyclic carbonate were achieved even different halogen-containingcompounds of the catalyst system of the disclosure were used.

The effects of using different transition metal salts in the catalystsystem on the conversion rate of cyclic carbonate are described inExample 5 and Examples 19 to 23 below.

EXAMPLES 19 TO 23

An epoxy compound (1,4-butanediol diglycidyl ether, BDGE, 15 g),triphenyl phosphine (PPh₃, 194 mg) and tetrabutylammonium bromide (TBAB,239 mg) and different transition metal salts were placed in a reactor,followed by sealing the reactor. Similar to Example 1 above, thereaction was conducted for 4 hours and the product was removed from thereactor after the reactor had return to room temperature and atmosphericpressure. The conversion rate of the cyclic carbonate of the product wasanalyzed by ¹ H NMR spectrum and was recorded in Table 6.

TABLE 6 (the amount of transition metal salts was 10 mmol % of the epoxycompound) Organic Halogen- Phosphine Containing Ligand Compound ReactionConversion Transition Molar Molar Temperature Rate Example Metal SaltType ratio Type Ratio (° C.) (%) 19 RhCl₃ PPh₃ 2 TBAB 2 90 85 20Pd(OAc)₂ PPh₃ 2 TBAB 2 90 90 21 Zn(OAc)₂ PPh₃ 2 TBAB 2 90 >99 22 RuCl₂PPh₃ 2 TBAB 2 90 88 23 FeCl₂ PPh₃ 2 TBAB 2 90 91

Based on the results summarized in Table 6, good conversion rates ofcyclic carbonate were achieved, even different transition metal salts ofthe catalyst system of the disclosure were used.

According to the disclosure, a highly effective catalyst system isformed with the application of an organic phosphine ligand and atransition metal salt, and the resulting catalyst system allows carbondioxide and an epoxy compound to undergo a cyclo-addition reaction undera moderate reaction condition for generating a cyclic carbonate compoundwith high yield. The catalyst system can further include ahalogen-containing compound. Further, the catalyst system of thedisclosure is precluded from using expensive metal ions for thereaction; hence, the cyclic carbonate produced is readily be used as rawmaterial for the fabrication of polycarbonate resin, abrogating therequisite of recycling the catalyst.

It will be apparent to those skilled in the art that variousmodifications and variations can be made to the structure of thedisclosure without departing from the scope or spirit of the disclosure.In view of the foregoing, it is intended that the disclosure covermodifications and variations of this disclosure provided they fallwithin the scope of the following claims and their equivalents.

What is claimed is:
 1. A catalyst system comprising: a transition metalsalt, comprising a halo group, an acetate group, or a combinationthereof; and an organic phosphine ligand, wherein a molar ratio of theorganic phosphine ligand to the transition metal salt is greater than 0and less than or equal to
 50. 2. The catalyst system of claim 1, whereinthe organic phosphine ligand comprises triphenyl phosphine (PPh₃),triphenyl phosphine oxide (OPPh₃), Poly(dipropylene glycol) phenylphosphite, tricyclohexyl phosphine (PCy₃), Tris(2,4-di-tert-butylphenyl) phosphite, triphenyl phosphite, ordiphenylmethyl phosphine.
 3. The catalyst system of claim 1, wherein thetransition metal salt comprises CoBr₂, RhCl₃, RuCl₂, FeCl₂, FeCl₃,AlCl₃, TiCl₄, PdX_(n), ScX₂, ScX₃, VX_(n), ZnX₂, CuX₂, SnX₂, ZrX_(n),MoX_(n), WX_(n), PtX_(n), or BiX_(n), wherein X represents chlorine,bromine, or iodine, n is greater than 1 and less than or equal to
 6. 4.The catalyst system of claim 1, wherein the transition metal saltcomprises Co(OAc)₂, Zn(OAc)₂, Pd(OAc)₂, Fe(OAc)₂, Fe(OAc)₃, Cu(OAc)₂,Cs(OAc), Rh(OAc)₂(dimer), Pb(OAc)₂, Sb(OAc)₃, La(OAc)₃, Bi(OAc)₃,Cd(OAc)₂, Y(OAc)₃, or Sc(OAc)₃.
 5. The catalyst system of claim 1further comprises a halogen-containing compound.
 6. The catalyst systemof claim 5, wherein a molar ratio of the halogen-containing compound tothe transition metal salt is greater than 0 but less than or equal to50.
 7. The catalyst system of claim 5, wherein the halogen-containingcompound comprises tetrabutylammonium chloride, (TBAC),tetrabutylammonium bromide (TBAB), tetrabutylammonium iodide (TBAI),anilinium chloride, benzalkonium chloride, benzoxonium chloride,cetrimonium chloride, cetylpyridinium chloride, choline chloride,didecyl dimethyl ammonium chloride, dimethyl dioctadecyl ammoniumchloride, stearalkonium chloride, tetraethylammonium bromide, domiphenbromide, benzododecinium bromide,(1-ethoxy-1-oxohexadecan-2-yl)-trimethylazanium bromide, cetrimoniumbromide, emepronium bromide, tetrabutylammonium tribromide,tetraoctylammonium bromide, thonzonium bromide, dithiazanine iodide,methiodide, or tetraethylammonium iodide.